Process for the production of metallic sulfids.



CHARLES OWEN GRIFFITH, F BCCKVILLE, WORMI'I, SCOTLAND.

PROCESS FOR REPRODUCTION OF METALLIC SULFIDS.

1V0 Drawing.

' Processes for the Production of Metallic is performed as follows :--A

Sulfids, of which the fication.

This invention relates to the production of metallic sulfids and has for its object to provide a process whereby sufids of metals may be produced by an electrical process.

According to this invention, I employ a cell in which is placed a metal plate or the like forming the anode, the cathode being formed by a plate or the like ofthe same metal coated or incrusted in Whole or in part, with sulfur.

In one manner of carrying out my process I employ a zinc anode of round, flat, or other suitableeection and a cathode formed of a stick or plate of zinc covered with sulfur. As an electrolyte I use a solution of ammonium chlorid or other suitable chlorid with or without the addition of other agents. To the anode I connect the positive conductor of a generator or other source of current and to the cathode I connect the negative conductor. Upon the current passing through the cell sulfureted hydrogen appears to be given oif at the cathode, and zinc sulfid is deposited in the cell, from whence it may be collected and treated so as to eliminate any impurities.

The chief difliculties attending the manu: facture of metallic sulfids by electrolysis are connected with the elimination or avoidance of impurities and my process goes further in attaining this object than any I know of, because the anode andcathode are the only metal introduced into the cell and they are formed of the metal of which it is desired to obtain the sulfid. My preferred manner of applying the cathode covering of sulfur,

shallow crucible of convenient size, or a vessel made of the clay or earth from which crucibles are mostly made, is used in melting the sulfur in preference to an iron or tin plate vessel, which if heated without extreme care causes impurities to be formed, besides which the vessel becomes very quickly useless by OX1- dation. I use the best quality of rock sulfur, and, when heat is applied until it has melted, I then place the-metal plate to be coated following is a speci- Specificatidn of Letters Patent.

drawn -and allowed to cool.

Patented Apr. 2, 191%.

Application filed June 7, 1917. Serial No. 173,309.

'face downward touching the molten sulfur for a few moments, it afterward being with- It is then and the operation repeated until a coating of the desired thickness has been obtained. It depends upon the strength of current used how much of the plate should be coated. In my original experiment the only current available was a very strong one and the late, which was about 3 inches in area, 1% inches thick, was only partly covered with sulfur about i thick. The result was that along with the sulfid formed there were metallic deposits dipped again from the anode which were difiicult to remove.

By coating the rest of the plate with a thin film of sulfur I found that the sulfid was produced free of metallic deposit. By a careful regulation of the current, however, 'and keeping it constantly below 1 volts and 4: amperes at a temperature of 50 C. to 70 C. and at of above 1 volt and 2 amperes, I found it necessary to coat only part of the plate either in the manner above described or by pouring'the melted sulfur into a mold and placing the block thus formed (after dipping it into the melted sulfur) upon the metal. When only part of the metal is coated it does not appear to make much difference how thick the block is, provided it is maintained in position. I prefer this latter method, as the sulfur lasts longerand as the electrolyte seldom requires to be renewed.

Temperature, strength of current V and method of coating are important in obtain ing the best colors of the various sulfids. The figures I have given apply particularly well in the case of antimony, and generally speaking to all the other sulfide. Should these conditions not be strictly observed,

particularly in the case of antimony H S is tion with the production of sulfid of zinc, but I may find that some other agent might be more suitable.

For instance as an electrolyte, in the case of antimony, I use sodium chlorid, ammonium chlorid or antimony trichlorid, and in the case of zinc, iron, lead, copper, cadmium, silver, arsenic and mercury, sodium chlorid, or ammonium chlorid, may be used. I have also tried the chlorid of the metal of which it is desired to obtain the sulfid and this appears to do quite well either alone or in conjunction with sodium chlorid or ammonium chlorid.

I claim 1. A process for the production of metallic sulfids consisting of passing an electrical current through a cell provided with an electrolyte and in which the anode and cathmemes ode are formed of the same kind of metal,

the cathode being provided with sulfur.

2. A process or the production of sulfid of zinc in which the anode and cathode are of zinc and are Inmersed in a cathode being provided with sulfur.

3. A process for the production of sulfid of zinc in which the anode and cathode are formed of'zinc and are immersed in a chlorid, the cathode being partly coated with sulfur.

Si ed at Dundee, in the county of Forfar, c7otland, this sixteenth day of May, A. D. 191

CHARLES OWEN GRIFFITH.

Witnesses:

JESSIE MORTON, THEODORE WILLIAM DRUBBLE.

chlorid, the p 

